Analysis of F response in upper motoneurone lesions.
The F response can provide a measure of motoneurone excitability (MNE) and so it may be used to investigate upper motoneurone disorders. This report studies the F-wave configuration in patients with stroke to evaluate the changes of the central excitability of the motoneurones at different times after an acute cerebral insult. Various parameters of the F response, including amplitude (absolute and F%/M), duration, and persistence have been determined in 26 patients with unilateral hemiplegia and in 32 healthy subjects of both sexes in the same age range. The investigation was carried out applying a series of 20 supramaximal stimuli at 0.5 Hz on tibial and ulnar nerves bilaterally. In all patients a detailed clinical examination and a CT scan were performed. Our results indicate that an initial stage of reduced spinal motoneuron excitability evidenced by a decreased F amplitude and persistence was present in the early phases after a stroke, followed within 90 days by an enhanced MNE. Moreover, F-wave amplitude shows a positive correlation with weakness and increased tone.
Fierro
B
B
Neurology Clinic, University of Palermo, Italy.
Raimondo
D
D
Modica
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006429:Hemiplegia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology; D009132:Muscles / Q000294:innervation; D009468:Neuromuscular Diseases / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012026:Reflex, Stretch / Q000502:physiology; D013979:Tibial Nerve / Q000503:physiopathology; D014459:Ulnar Nerve / Q000503:physiopathology